System and method for beam directional nulling

ABSTRACT

Methods and apparatuses in a wireless communication system. A base station (BS) includes a transceiver and a processor. The processor is configured to transmit a common beam to at least one user equipment (UE). The processor is also configured to configure the common beam to have a null area in a direction of a satellite earth station, the null area defining a space within a coverage area of the common beam in which a signal from the common beam is suppressed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

The present application claims priority to U.S. Provisional PatentApplication No. 63/227,721, filed on Jul. 30, 2021. The content of theabove-identified patent document is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to a diverse networks and, morespecifically, the present disclosure relates to a beam nulling fornon-terrestrial systems.

BACKGROUND

Wireless communication has been one of the most successful innovationsin modern history. Recently, the number of subscribers to wirelesscommunication services exceeded five billion and continues to growquickly. The demand of wireless data traffic is rapidly increasing dueto the growing popularity among consumers and businesses of smart phonesand other mobile data devices, such as tablets, “note pad” computers,net books, eBook readers, and machine type of devices. In order to meetthe high growth in mobile data traffic and support new applications anddeployments, improvements in radio interface efficiency, coverage, andquality of service are of paramount importance.

SUMMARY

The present disclosure generally relates to diverse networks and, morespecifically, the present disclosure relates to beam nulling fornon-terrestrial systems.

In another embodiment, a base station (BS) in a wireless communicationsystem is provided. The BS includes a transceiver and a processor. Theprocessor is configured to transmit a common beam to at least one userequipment (UE). The processor is also configured to configure the commonbeam to have a null area in a direction of a satellite earth station,the null area defining a space within a coverage area of the common beamin which a signal from the common beam is suppressed.

In one embodiment, a method of a base station (BS) a wirelesscommunication system is provided. The method includes transmitting, viaa transceiver, a common beam to at least one user equipment (UE). Themethod also includes configuring the common beam to have a null area ina direction of a satellite earth station, the null area defining a spacewithin a coverage area of the common beam in which a signal from thecommon beam is suppressed.

In yet another embodiment, a non-transitory computer readable medium isprovided. The non-transitory computer readable medium includesinstructions that, when executed by at least one processor, areconfigured to cause the at least one processor to: transmit a commonbeam to at least one user equipment (UE); and configure the common beamto have a null area in a direction of a satellite earth station, thenull area defining a space within a coverage area of the common beam inwhich a signal from the common beam is suppressed.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system, or partthereof that controls at least one operation. Such a controller may beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items may be used,and only one item in the list may be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, a reference is now made to the following description takenin conjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure;

FIG. 2 illustrates an example gNB according to embodiments of thepresent disclosure;

FIG. 3 illustrates an example UE according to embodiments of the presentdisclosure;

FIGS. 4A and 4B illustrate example wireless transmit and receive pathsaccording to this disclosure;

FIG. 5 illustrates an example antenna according to embodiments of thepresent disclosure;

FIGS. 6A and 6B illustrate an example interference reduction in wirelesscommunications network having terrestrial and non-terrestrial stationsaccording to embodiments of the present disclosure;

FIG. 7 illustrates an example beam nulling grid according to embodimentsof the present disclosure;

FIG. 8 illustrates processes for beam nulling according to embodimentsof the present disclosure;

FIG. 9 illustrates an example of peak gain, nulling level, and nullingwidth according to embodiments of the present disclosure;

FIGS. 10 and 11 illustrate examples of simulation results thatillustrate an example common beam nulling method according toembodiments of the present disclosure;

FIG. 12 illustrates an example of coverage partition and initial weightsfor a single nulling region; and

FIG. 13 illustrates an example of coverage partition and initial weightsfor two nulling regions.

DETAILED DESCRIPTION

FIGS. 1 through 13 , discussed below, and the various embodiments usedto describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems and to enable various verticalapplications, efforts have been made to develop and deploy an improved5G/NR or pre-5G/NR communication system. Therefore, the 5G/NR orpre-5G/NR communication system is also called a “beyond 4G network” or a“post LTE system.” The 5G/NR communication system is considered to beimplemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60 GHzbands, so as to accomplish higher data rates or in lower frequencybands, such as 6 GHz, to enable robust coverage and mobility support.Aspects of the present disclosure may also be applied to deployment of5G communication system, 6G or even later release which may useterahertz (THz) bands. To decrease propagation loss of the radio wavesand increase the transmission distance, the beamforming, massivemultiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO),array antenna, an analog beam forming, large scale antenna techniquesare discussed in 5G/NR communication systems.

In addition, in 5G/NR communication systems, development for systemnetwork improvement is under way based on advanced small cells, cloudradio access networks (RANs), ultra-dense networks, device-to-device(D2D) communication, wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), reception-endinterference cancelation and the like. In the 5G system, Hybrid FSK andQAM Modulation (FQAM) and sliding window superposition coding (SWSC) asan advanced coding modulation (ACM), and filter bank multi carrier(FBMC), non-orthogonal multiple access(NOMA), and sparse code multipleaccess (SCMA) as an advanced access technology have been developed.

The discussion of 5G systems and frequency bands associated therewith isfor reference as certain embodiments of the present disclosure may beimplemented in 5G systems. However, the present disclosure is notlimited to 5G systems or the frequency bands associated therewith, andembodiments of the present disclosure may be utilized in connection withany frequency band. For example, aspects of the present disclosure mayalso be applied to deployment of 5G communication systems, 6G or evenlater releases which may use terahertz (THz) bands.

In many cases, cellular networks are deployment in locations wheresatellite earth-stations (ES) exist. Cellular operation bands can beadjacent to ES operation band. There are harsh constraints on the amountof interference that ES can tolerate in their band of operation. Eventhough cellular networks are operating in a different adjacent band, outof band (OOB) emission still affects ES. Hence, transmission back-off isrequired to avoid OOB interference.

Power reduction is one way to reduce interference to ESs, which,however, will cause a smaller coverage and performance degradation. Inorder to reduce interference to ESs while maintaining coverage andmitigating performance degradation, common beam and SRS-based data beamcan be designed so that the radiation power is reduced directionallytowards the ES, referring to as directional nulling. Methods ofdirectional nulling of common beam and SRS-based data beam need to bedesigned.

Embodiments of the present disclosure provide methods of beamdirectional nulling. The Methods for common beam directional nullinginclude nulling a common beam in one or more directions. The nullingwidth can be accurately controlled, and the nulling level can beguaranteed by reducing beam gain in the nulling direction to a certainlevel with respect to the peak beam gain. For SRS-based data beamdirectional nulling, two beamforming algorithms are disclosed to nulldata beam in the ES direction based on the CSI measured via a soundingreference signal (SRS). Certain embodiments of the present disclosurecan be applied but not limited to interference reduction to satelliteearth stations, which should be considered in an inclusive mannerwithout exclusion of other use cases.

FIGS. 1-3 below describe various embodiments implemented in wirelesscommunications systems and with the use of orthogonal frequency divisionmultiplexing (OFDM) or orthogonal frequency division multiple access(OFDMA) communication techniques. The descriptions of FIGS. 1-3 are notmeant to imply physical or architectural limitations to the manner inwhich different embodiments may be implemented. Different embodiments ofthe present disclosure may be implemented in any suitably-arrangedcommunications system.

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure. The embodiment of the wireless network shownin FIG. 1 is for illustration only. Other embodiments of the wirelessnetwork 100 could be used without departing from the scope of thisdisclosure.

As shown in FIG. 1 , the wireless network includes a gNB 101 (e.g., basestation, BS), a gNB 102, and a gNB 103. The gNB 101 communicates withthe gNB 102 and the gNB 103. The gNB 101 also communicates with at leastone network 130, such as the Internet, a proprietary Internet Protocol(IP) network, or other data network. In certain embodiments, the gNB 103is a non-terrestrial BS. For example, gNB 103 can be a satellitepositioned in a geosynchronous equatorial orbit (geostationary orbit,GEO) or in a low earth orbit (LEO). Additionally, gNB 103 can be asatellite orbiting station coupled to a satellite earth station.

The gNB 102 provides wireless broadband access to the network 130 for afirst plurality of UEs within a coverage area 120 of the gNB 102. Thefirst plurality of UEs includes a UE 111, which may be located in asmall business; a UE 112, which may be located in an enterprise (E); aUE 113, which may be located in a WiFi hotspot (HS); a UE 114, which maybe located in a first residence (R); a UE 115, which may be located in asecond residence (R); and a UE 116, which may be a mobile device (M),such as a cell phone, a wireless laptop, a wireless PDA, or the like.The gNB 103 provides wireless broadband access to the network 130 for asecond plurality of UEs within a coverage area 125 of the gNB 103. Thecoverage area 125 provided by gNB 103 can be part of a non-terrestrialnetwork (NTN). The second plurality of UEs includes the UE 115 and theUE 116. In some embodiments, one or more of the gNBs 101-103 maycommunicate with each other and with the UEs 111-116 using 5G/NR, LTE,LTE-A, WiMAX, WiFi, or other wireless communication techniques.

Depending on the network type, the term “base station” or “BS” can referto any component (or collection of components) configured to providewireless access to a network, such as transmit point (TP),transmit-receive point (TRP), an enhanced base station (eNodeB or eNB),a 5G/NR base station (gNB), a macrocell, a femtocell, a WiFi accesspoint (AP), or other wirelessly enabled devices. Base stations mayprovide wireless access in accordance with one or more wirelesscommunication protocols, e.g., 5G/NR 3GPP new radio interface/access(NR), long term evolution (LTE), LTE advanced (LTE-A), high speed packetaccess (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience,the terms “BS” and “TRP” are used interchangeably in this patentdocument to refer to network infrastructure components that providewireless access to remote terminals. Also, depending on the networktype, the term “user equipment” or “UE” can refer to any component suchas “mobile station,” “subscriber station,” “remote terminal,” “wirelessterminal,” “receive point,” or “user device.” For the sake ofconvenience, the terms “user equipment” and “UE” are used in this patentdocument to refer to remote wireless equipment that wirelessly accessesa BS, whether the UE is a mobile device (such as a mobile telephone orsmartphone) or is normally considered a stationary device (such as adesktop computer or vending machine).

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with gNBs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the gNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116include circuitry, programing, or a combination thereof for beamdirectional nulling. In certain embodiments, and one or more of the gNBs101-103 includes circuitry, programing, or a combination thereof forbeam directional nulling.

Although FIG. 1 illustrates one example of a wireless network, variouschanges may be made to FIG. 1 . For example, the wireless network couldinclude any number of gNBs and any number of UEs in any suitablearrangement. Also, the gNB 101 could communicate directly with anynumber of UEs and provide those UEs with wireless broadband access tothe network 130. Similarly, each gNB 102-103 could communicate directlywith the network 130 and provide UEs with direct wireless broadbandaccess to the network 130. Further, the gNBs 101, 102, and/or 103 couldprovide access to other or additional external networks, such asexternal telephone networks or other types of data networks.

FIG. 2 illustrates an example gNB 103 according to embodiments of thepresent disclosure. The embodiment of the gNB 103 illustrated in FIG. 2is for illustration only, and the gNBs 101 and 102 of FIG. 1 could havethe same or similar configuration. However, gNBs come in a wide varietyof configurations, and FIG. 2 does not limit the scope of thisdisclosure to any particular implementation of a gNB.

As shown in FIG. 2 , the gNB 103 includes multiple antennas 205 a-205 n,multiple RF transceivers 210 a-210 n, transmit (TX) processing circuitry215, and receive (RX) processing circuitry 220. The gNB 103 alsoincludes a controller/processor 225, a memory 230, and a backhaul ornetwork interface 235.

The RF transceivers 210 a-210 n receive, from the antennas 205 a-205 n,incoming RF signals, such as signals transmitted by UEs in the network100. The RF transceivers 210 a-210 n down-convert the incoming RFsignals to generate IF or baseband signals. The IF or baseband signalsare sent to the RX processing circuitry 220, which generates processedbaseband signals by filtering, decoding, and/or digitizing the basebandor IF signals. The RX processing circuitry 220 transmits the processedbaseband signals to the controller/processor 225 for further processing.

The TX processing circuitry 215 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 225. The TX processing circuitry 215 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 210 a-210 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 215 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or otherprocessing devices that control the overall operation of the gNB 103.For example, the controller/processor 225 could control the reception ofUL channel signals and the transmission of DL channel signals by the RFtransceivers 210 a-210 n, the RX processing circuitry 220, and the TXprocessing circuitry 215 in accordance with well-known principles. Thecontroller/processor 225 could support additional functions as well,such as more advanced wireless communication functions. For instance,the controller/processor 225 could support beam forming or directionalrouting operations in which outgoing/incoming signals from/to multipleantennas 205 a-205 n are weighted differently to effectively steer theoutgoing signals in a desired direction. Any of a wide variety of otherfunctions could be supported in the gNB 103 by the controller/processor225.

The controller/processor 225 is also capable of executing programs andother processes resident in the memory 230, such as an OS. Thecontroller/processor 225 can move data into or out of the memory 230 asrequired by an executing process.

The controller/processor 225 is also coupled to the backhaul or networkinterface 235. The backhaul or network interface 235 allows the gNB 103to communicate with other devices or systems over a backhaul connectionor over a network. The interface 235 could support communications overany suitable wireless connection(s). When disposed as part of aterrestrial network, such as gNB 101 and gNB 102, The interface 235could support communications over any suitable wired or wirelessconnection(s). For example, when the gNB 103 is implemented as part of acellular communication system (such as one supporting 5G/NR, LTE, orLTE-A), the interface 235 could allow the gNB 103 to communicate withother gNBs over a wireless backhaul connection while gNB 101 and gNB 102can communicate with other gNBs over a wired or wireless backhaulconnection. When the one or the gNBs 101-103 is implemented as an accesspoint, the interface 235 could allow the gNB 102 to communicate over awired or wireless local area network or over a wired or wirelessconnection to a larger network (such as the Internet). The interface 235includes any suitable structure supporting communications over a wiredor wireless connection, such as an Ethernet or RF transceiver.

The memory 230 is coupled to the controller/processor 225. Part of thememory 230 could include a RAM, and another part of the memory 230 couldinclude a flash memory or other ROM.

Although FIG. 2 illustrates one example of gNB 103, various changes maybe made to FIG. 2 . For example, the gNB 103, and respectively gNB 101and 102 as part of terrestrial networks, could include any number ofeach component shown in FIG. 2 . As a particular example, an accesspoint could include a number of interfaces 235, and thecontroller/processor 225 could support routing functions to route databetween different network addresses. As another particular example,while shown as including a single instance of TX processing circuitry215 and a single instance of RX processing circuitry 220, the gNB 102could include multiple instances of each (such as one per RFtransceiver). Also, various components in FIG. 2 could be combined,further subdivided, or omitted and additional components could be addedaccording to particular needs.

FIG. 3 illustrates an example UE 116 according to embodiments of thepresent disclosure. The embodiment of the UE 116 illustrated in FIG. 3is for illustration only, and the UEs 111-115 of FIG. 1 could have thesame or similar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 3 does not limit the scope of this disclosureto any particular implementation of a UE.

As shown in FIG. 3 , the UE 116 includes an antenna 305, a radiofrequency (RF) transceiver 310, TX processing circuitry 315, amicrophone 320, and RX processing circuitry 325. The UE 116 alsoincludes a speaker 330, a processor 340, an input/output (I/O) interface(IF) 345, a touchscreen 350, a display 355, and a memory 360. The memory360 includes an operating system (OS) 361 and one or more applications362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by a gNB of the network 100. The RF transceiver 310down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 325, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 325 transmits the processed basebandsignal to the speaker 330 (such as for voice data) or to the processor340 for further processing (such as for web browsing data).

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 340.The TX processing circuitry 315 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 310 receives the outgoing processed basebandor IF signal from the TX processing circuitry 315 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 305.

The processor 340 can include one or more processors or other processingdevices and execute the OS 361 stored in the memory 360 in order tocontrol the overall operation of the UE 116. For example, the processor340 could control the reception of DL channel signals and thetransmission of UL channel signals by the RF transceiver 310, the RXprocessing circuitry 325, and the TX processing circuitry 315 inaccordance with well-known principles. In some embodiments, theprocessor 340 includes at least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as processes for beammanagement. The processor 340 can move data into or out of the memory360 as required by an executing process. In some embodiments, theprocessor 340 is configured to execute the applications 362 based on theOS 361 or in response to signals received from gNBs or an operator. Theprocessor 340 is also coupled to the I/O interface 345, which providesthe UE 116 with the ability to connect to other devices, such as laptopcomputers and handheld computers. The I/O interface 345 is thecommunication path between these accessories and the processor 340.

The processor 340 is also coupled to the touchscreen 350 and the display355. The operator of the UE 116 can use the touchscreen 350 to enterdata into the UE 116. The display 355 may be a liquid crystal display,light emitting diode display, or other display capable of rendering textand/or at least limited graphics, such as from web sites.

The memory 360 is coupled to the processor 340. Part of the memory 360could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes maybe made to FIG. 3 . For example, various components in FIG. 3 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 340 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 3 illustrates the UE 116 configured as amobile telephone or smartphone, UEs could be configured to operate asother types of mobile or stationary devices.

A communication system includes a downlink (DL) that refers totransmissions from a base station or one or more transmission points toUEs and an uplink (UL) that refers to transmissions from UEs to a basestation or to one or more reception points.

A time unit for DL signaling or for UL signaling on a cell is referredto as a slot and can include one or more symbols. A symbol can alsoserve as an additional time unit. A frequency (or bandwidth (BW)) unitis referred to as a resource block (RB). One RB includes a number ofsub-carriers (SCs). For example, a slot can have duration of 0.5milliseconds or 1 millisecond, include 14 symbols and an RB can include12 SCs with inter-SC spacing of 15 KHz or 30 KHz, and so on.

DL signals include data signals conveying information content, controlsignals conveying DL control information (DCI), and reference signals(RS) that are also known as pilot signals. A gNB transmits datainformation or DCI through respective physical DL shared channels(PDSCHs) or physical DL control channels (PDCCHs). A PDSCH or a PDCCHcan be transmitted over a variable number of slot symbols including oneslot symbol. For brevity, a DCI format scheduling a PDSCH reception by aUE is referred to as a DL DCI format and a DCI format scheduling aphysical uplink shared channel (PUSCH) transmission from a UE isreferred to as an UL DCI format.

A gNB transmits one or more of multiple types of RS including channelstate information RS (CSI-RS) and demodulation RS (DMRS). A CSI-RS isprimarily intended for UEs to perform measurements and provide channelstate information (CSI) to a gNB. For channel measurement, non-zeropower CSI-RS (NZP CSI-RS) resources are used. For interferencemeasurement reports (IMRs), CSI interference measurement (CSI-IM)resources associated with a zero power CSI-RS (ZP CSI-RS) configurationare used. A CSI process consists of NZP CSI-RS and CSI-IM resources.

A UE can determine CSI-RS transmission parameters through DL controlsignaling or higher layer signaling, such as radio resource control(RRC) signaling, from a gNB. Transmission instances of a CSI-RS can beindicated by DL control signaling or be configured by higher layersignaling. A DMRS is transmitted only in the BW of a respective PDCCH orPDSCH and a UE can use the DMRS to demodulate data or controlinformation.

FIG. 4A and FIG. 4B illustrate example wireless transmit and receivepaths according to this disclosure. In the following description, atransmit path 400 may be described as being implemented in a gNB (suchas the gNB 102), while a receive path 450 may be described as beingimplemented in a UE (such as a UE 116). However, it may be understoodthat the receive path 450 can be implemented in a gNB and that thetransmit path 400 can be implemented in a UE. In some embodiments, thereceive path 450 is configured to support adapting a channel sensingthreshold as described in embodiments of the present disclosure.

The transmit path 400 as illustrated in FIG. 4A includes a channelcoding and modulation block 405, a serial-to-parallel (S-to-P) block410, a size N inverse fast Fourier transform (IFFT) block 415, aparallel-to-serial (P-to-S) block 420, an add cyclic prefix block 425,and an up-converter (UC) 430. The receive path 450 as illustrated inFIG. 4B includes a down-converter (DC) 455, a remove cyclic prefix block460, a serial-to-parallel (S-to-P) block 465, a size N fast Fouriertransform (FFT) block 470, a parallel-to-serial (P-to-S) block 475, anda channel decoding and demodulation block 485.

As illustrated in FIG. 4A, the channel coding and modulation block 405receives a set of information bits, applies coding (such as alow-density parity check (LDPC) coding), and modulates the input bits(such as with quadrature phase shift keying (QPSK) or quadratureamplitude modulation (QAM)) to generate a sequence of frequency-domainmodulation symbols.

The serial-to-parallel block 410 converts (such as de-multiplexes) theserial modulated symbols to parallel data in order to generate Nparallel symbol streams, where N is the IFFT/FFT size used in the gNB102 and the UE 116. The size N IFFT block 415 performs an IFFT operationon the N parallel symbol streams to generate time-domain output signals.The parallel-to-serial block 420 converts (such as multiplexes) theparallel time-domain output symbols from the size N IFFT block 415 inorder to generate a serial time-domain signal. The add cyclic prefixblock 425 inserts a cyclic prefix to the time-domain signal. Theup-converter 430 modulates (such as up-converts) the output of the addcyclic prefix block 425 to an RF frequency for transmission via awireless channel. The signal may also be filtered at baseband beforeconversion to the RF frequency.

A transmitted RF signal from the gNB 102 arrives at the UE 116 afterpassing through the wireless channel, and reverse operations to those atthe gNB 102 are performed at the UE 116.

As illustrated in FIG. 4B, the down-converter 455 down-converts thereceived signal to a baseband frequency, and the remove cyclic prefixblock 460 removes the cyclic prefix to generate a serial time-domainbaseband signal. The serial-to-parallel block 465 converts thetime-domain baseband signal to parallel time domain signals. The size NFFT block 470 performs an FFT algorithm to generate N parallelfrequency-domain signals. The parallel-to-serial block 475 converts theparallel frequency-domain signals to a sequence of modulated datasymbols. The channel decoding and demodulation block 485 demodulates anddecodes the modulated symbols to recover the original input data stream.

Each of the gNBs 101-103 may implement a transmit path 400 asillustrated in FIG. 4A that is analogous to transmitting in the downlinkto UEs 111-116 and may implement a receive path 450 as illustrated inFIG. 4B that is analogous to receiving in the uplink from UEs 111-116.Similarly, each of UEs 111-116 may implement the transmit path 400 fortransmitting in the uplink to the gNBs 101-103 and may implement thereceive path 450 for receiving in the downlink from the gNBs 101-103.

Each of the components in FIG. 4A and FIG. 4B can be implemented usingonly hardware or using a combination of hardware and software/firmware.As a particular example, at least some of the components in FIG. 4A andFIG. 4B may be implemented in software, while other components may beimplemented by configurable hardware or a mixture of software andconfigurable hardware. For instance, the FFT block 470 and the IFFTblock 415 may be implemented as configurable software algorithms, wherethe value of size N may be modified according to the implementation.

Furthermore, although described as using FFT and IFFT, this is by way ofillustration only and may not be construed to limit the scope of thisdisclosure. Other types of transforms, such as discrete Fouriertransform (DFT) and inverse discrete Fourier transform (IDFT) functions,can be used. It may be appreciated that the value of the variable N maybe any integer number (such as 1, 2, 3, 4, or the like) for DFT and IDFTfunctions, while the value of the variable N may be any integer numberthat is a power of two (such as 1, 2, 4, 8, 16, or the like) for FFT andIFFT functions.

Although FIG. 4A and FIG. 4B illustrate examples of wireless transmitand receive paths, various changes may be made to FIG. 4A and FIG. 4B.For example, various components in FIG. 4A and FIG. 4B can be combined,further subdivided, or omitted and additional components can be addedaccording to particular needs. Also, FIG. 4A and FIG. 4B are meant toillustrate examples of the types of transmit and receive paths that canbe used in a wireless network. Any other suitable architectures can beused to support wireless communications in a wireless network.

FIG. 5 illustrates an example antenna blocks 500 according toembodiments of the present disclosure. The embodiment of the antenna 500illustrated in FIG. 5 is for illustration only. FIG. 5 does not limitthe scope of this disclosure to any particular implementation of theantenna 500. In certain embodiments, one or more of gNB 102 or UE 116include the antenna 500. For example, one or more of antenna 205 and itsassociated systems or antenna 305 and its associated systems can beconfigured the same as antenna 500.

Rel.14 LTE and Rel.15 NR support up to 32 CSI-RS antenna ports whichenable an eNB to be equipped with a large number of antenna elements(such as 64 or 128). In this case, a plurality of antenna elements ismapped onto one CSI-RS port. For mmWave bands, although the number ofantenna elements can be larger for a given form factor, the number ofCSI-RS ports—which can correspond to the number of digitally precodedports—tends to be limited due to hardware constraints (such as thefeasibility to install a large number of ADCs/DACs at mmWavefrequencies).

In the example shown in FIG. 5 , the antenna 500 includes analog phaseshifters 505, an analog beamformer (BF) 510, a hybrid BF 515, a digitalBF 520, and one or more antenna arrays 525. In this case, one CSI-RSport is mapped onto a large number of antenna elements in antenna arrays525, which can be controlled by the bank of analog phase shifters 505.One CSI-RS port can then correspond to one sub-array which produces anarrow analog beam through analog beamforming by analogy BF 510. Theanalog beam can be configured to sweep 530 across a wider range ofangles by varying the phase shifter bank 505 across symbols orsubframes. The number of sub-arrays (equal to the number of RF chains)is the same as the number of CSI-RS ports N_(CSI-PORT). A digital BF 515performs a linear combination across N_(CSI-PORT) analog beams tofurther increase precoding gain. While analog beams are wideband (hencenot frequency-selective), digital precoding can be varied acrossfrequency sub-bands or resource blocks.

Since the above system utilizes multiple analog beams for transmissionand reception (wherein one or a small number of analog beams areselected out of a large number, for instance, after a trainingduration—to be performed from time to time), the term “multi-beamoperation” is used to refer to the overall system aspect. This includes,for the purpose of illustration, indicating the assigned DL or ULtransmit (TX) beam (also termed “beam indication”), measuring at leastone reference signal for calculating and performing beam reporting (alsotermed “beam measurement” and “beam reporting”, respectively), andreceiving a DL or UL transmission via a selection of a correspondingreceive (RX) beam.

Additionally, the antenna 500 system is also applicable to higherfrequency bands such as >52.6 GHz (also termed the FR4). In this case,the system can employ only analog beams. Due to the O2 absorption lossaround 60 GHz frequency (˜10 decibels (dB) additional loss @100 mdistance), larger number of and sharper analog beams (hence largernumber of radiators in the array) will be needed to compensate for theadditional path loss.

FIGS. 6A and 6B illustrate an example interference reduction in wirelesscommunications network having terrestrial and non-terrestrial stationsaccording to embodiments of the present disclosure. The embodiment ofthe wireless communications network 600 shown in FIGS. 6A and 6B are forillustration only. Other embodiments could be used without departingfrom the scope of the present disclosure.

In many cases, cellular networks are deployed in locations wheresatellite earth-stations (ES) 605 exist. In certain embodiments, ES 605is configured to perform satellite communications. The ES 605 isprimarily deployed to be fixed and receive-only for satellitecommunication.

Cellular operation bands, such as via gNB 102, can be adjacent to ES 605operation band. For example, 5G emission, in coverage area 610, from gNB102 can interfere with the ES 605. Additionally, there are harshconstraints on the amount of interference that 605 can tolerate in theirband of operation. That is, the 5G massive MIMO system on C-band cancause some interference to the ES 605 for satellite communication. TheFederal Communication Commission (FCC) has implemented regulations onthe C-Band emissions. To comply with the FCC regulations, the 5G massiveMIMO system needs to be designed to control the interference to the ES605, namely, for the satellite communication in C-band.

Power reduction is one way to reduce interference to the ES 605, which,however, will cause a smaller coverage and performance degradation. Eventhough cellular networks are operating in a different adjacent band, outof band (OOB) emission still affects ES 605, hence, transmission powerback-off may be required in some cases to avoid OOB interference. Incertain scenarios, to mitigate OOB interference, gNB 102 may performpower reduction and transmit to a reduced coverage area 615. Inresponse, the ES 605 continues to measure the interference while gNB 102continues to reduce the power so that the interference coming from gNB102 would comply with the regulations. A problem with this power backoff is that it deteriorates the through-put. That is, reducing the powerto reduce the interference may affect the performance of the system aswell.

In certain embodiments, to reduce interference to ES 605 whilemaintaining coverage in coverage area 610 and mitigating performancedegradation, a common beam can be designed so that the radiation powerfrom gNB 102 is reduced directionally towards the ES 605, referring toas directional nulling. The common beam is broadcasted by the networkfor Synchronization Signal and PBCH Blocks (SSBs) for synchronization,UE initial access, and system information. That is, in certainembodiments, gNB 102 uses a common beam design that is configured tocreate a null 620 in a direction of ES 605. The null area defines aspace within a coverage area of the common beam in which a signal fromthe common beam is suppressed. That is, the common beam is transmittedin each direction of the coverage area 610 except within an area of thenull 620. Embodiments of the present disclosure provide a design of acommon beam for directional nulling.

FIG. 7 illustrates an example beam nulling grid according to embodimentsof the present disclosure. The embodiment of the beam nulling grid 700shown in FIG. 7 is for illustration only. Other embodiments could beused without departing from the scope of the present disclosure.

In certain embodiments, for common beam directional nulling, thecoverage area of a common beam is partitioned into a grid 700 ofequal-sized units up to a certain granularity. Given a horizontal widthand a vertical width, the nulling region 705 can be covered by at leastone unit. The antenna port beamforming weights can be optimized orimproved by maximizing or changing a weighted sum of beam gain utilityfunctions, so that the beam gain corresponding to the optimized/improvedbeamforming weights is reduced in the nulling region.

FIG. 8 illustrates processes for beam nulling according to embodimentsof the present disclosure. While the flow chart depicts a series ofsequential steps, unless explicitly stated, no inference should be drawnfrom that sequence regarding specific order of performance, performanceof steps or portions thereof serially rather than concurrently or in anoverlapping manner, or performance of the steps depicted exclusivelywithout the occurrence of intervening or intermediate steps. The process800 depicted in the example depicted is implemented by a processor andtransmitter chain in, for example, a base station.

In operation 805, common beam coverage area is partitioned into a grid,nulling units are identified, and initial weights are assigned. Thecoverage area of a common beam can be defined as the antenna 3 dB or anyother gain defined beam width, and presented by the boresight angle andangular coverage width. In one example, shown in FIG. 7 , the boresight710 (center) of the coverage area is denoted (φ_(c), θ_(c)), where φ_(c)and θ_(c) are the azimuth angle and elevation angle, respectively. Thehorizontal angular coverage width is denoted φ_(W) and the verticalangular coverage width is denoted θ_(W). The coverage area ispartitioned into a grid 700 of H×V units, where each unit is a rectangleof horizontal angular width φ_(W)/H and vertical angular width θ_(W)/V.The (i, j)-th unit covers the range

$\lbrack {{\varphi_{c} - \frac{{\varphi}_{w}}{2} + {( {i - 1} )\frac{{\varphi}_{w}}{H}}},{\varphi_{c} - \frac{{\varphi}_{w}}{2} + {i\frac{{\varphi}_{w}}{H}}}} \rbrack$

in the azimuth domain and the range

$\lbrack {{\theta_{c} - \frac{{\theta}_{w}}{2} + {( {j - 1} )\frac{{\theta}_{w}}{V}}},{\theta_{c} - \frac{{\theta}_{w}}{2} + {j\frac{{\theta}_{w}}{V}}}} \rbrack$

in the elevation domain, for 1≤i≤H, 1≤j≤V.

A nulling region 705 can be presented by nulling direction ({tilde over(φ)}_(c), {tilde over (θ)}_(c)), where {tilde over (φ)}_(c) and {tildeover (θ)}_(c) are the azimuth angle and elevation angle, respectively,and horizontal nulling width {tilde over (φ)}_(W) and vertical nullingwidth {tilde over (θ)}_(W). Any unit overlapping with the nulling regionis identified as a nulling unit, so that the nulling region is coveredby at least one unit in the coverage grid. The granularity of the gridcan be tuned by choosing suitable values for H and V to cover thenulling region as precisely as possible. For more than one noncontiguousnulling regions, a set of nulling directions and widths is adopted topresent the nulling regions. And the nulling units are identified in thegrid accordingly. FIG. 7 shows an example of two noncontiguous nullingregions 705 marked as deep grey, and the corresponding nulling units 715marked as light grey.

Each unit is assigned an initial weight, denoted a_(ij). A non-nullingunit 720 is assigned a positive weight and a nulling unit 715 isassigned a negative weight, for example 1 and −1, respectively. In theexample shown in FIG. 7 , two non-nulling units are indicated byreference number 720 for clarity; however, in grid 700 all non-shadedunits can represent non-nulling units.

In operation 810, the antenna port beamforming weight vector w of thecommon beam can be calculated by maximizing a weighted sum of beam gainutility functions, expressed as:

$\begin{matrix}{{\sum\limits_{i = 1}^{H}{\sum\limits_{j = 1}^{V}{a_{ij}{f( {G( {w,i,j} )} )}}}},} & (1)\end{matrix}$

In Equation 1, G(w, i, j) denotes the beam gain of unit (i, j), which isa function of beamforming vector w, and f is a monotonic non-decreasingfunction. By maximizing this objective function, the beam gain of thenulling region is reduced due to the negative weights. Given a set ofweights {a_(ij)}, the beamforming vector w can be obtained by solvingthe maximization problem via K-means algorithm. Then, the correspondingbeam gain {G(w, i, j)} can be calculated.

In operation 815, a determination is made as to whether the nullingwidth is satisfied. If the nulling width is satisfied, the process endsat operation 820. If the nulling width is not satisfied, the weights areupdated in operation 825 and the process returns to operation 810. Theactual nulling width can be checked based on the obtained beam gain. Thepeak beam gain can be defined as the maximum beam gain of the commonbeam without nulling. The horizontal nulling width is the angular widthbetween two points where the beam gain is reduced by the nulling levelfrom the peak gain. The gNB 102 can determine whether the nulling widthsatisfies a predetermined threshold for a specified nulling level.

FIG. 9 illustrates an example of peak gain, nulling level, and nullingwidth according to embodiments of the present disclosure. The embodimentof the peak gain, nulling level, and nulling width 900 shown in FIG. 9is for illustration only. Other embodiments could be used withoutdeparting from the scope of the present disclosure.

In the example shown in FIG. 9 , for a set of weights {a_(ij)}, anulling level 905, and the beam gain obtained in operation 810, if thenulling width 910 does not satisfy the require width, operation 810 isrepeated with an updated set of the weights for the nulling units untilthe required nulling width 910 is satisfied. In certain embodiments, theweight of a nulling unit can be updated by a binary search algorithm.Specifically, a maximum value and a minimum value are defined for theweights of nulling units and denoted a_(max) and a_(min), respectively,which are negative values. If the nulling width 910 is smaller than therequired value, the weight a_(ij) for nulling unit (i, j) is updatedaccording to Equation 2:

$\begin{matrix} a_{ij}arrow{\frac{a_{ij} + a_{\min}}{2}.}  & (2)\end{matrix}$

If the nulling width 910 is larger than the required value, the weighta_(ij) for nulling unit (i, j) is updated. For example, the weighta_(ij) for nulling unit (i, j) can be updated according to Equation 3:

$\begin{matrix} a_{ij}arrow{\frac{a_{ij} + a_{\max}}{2}.}  & (3)\end{matrix}$

In certain embodiments, appropriate values are set for a_(max) anda_(min) so that the accurate nulling width can be achieved within acertain number of iterations.

FIGS. 10 and 11 illustrate examples of simulation results thatillustrate beam patterns for an example common beam nulling methodaccording to embodiments of the present disclosure. The example beampattern 1000 shown in FIG. 10 and the example beam pattern 1100 shown inFIG. 11 are for illustration only. Other examples could be used withoutdeparting from the scope of the present disclosure.

For a 4×4 antenna array, the boresight is (φ_(c)=180°, θ_(c)=90°) andthe coverage width is (φ_(W)=65°, θ_(W)=12°). The nulling region is atthe center of the coverage plane, which is partitioned into H×V=10×6units with initial weight as shown in FIG. 12 . Given nulling level 10dB and nulling width ({tilde over (φ)}_(W)12°, {tilde over (θ)}_(W)=4°),the beam pattern 1000 of the common beam nulled at the center region isshown in FIG. 10 . FIG. 12 illustrates an example of coverage partitionand initial weights for a single nulling region.

In another example, the coverage area partition and beam pattern 1100includes two noncontiguous nulling regions centering at ({tilde over(φ)}_(c1)=165°, {tilde over (θ)}_(c1)=90°) and ({tilde over(φ)}_(c2)=195°, {tilde over (θ)}_(c2)=90°) that are required withnulling level 10 dB and nulling width ({tilde over (φ)}_(W)=12°, {tildeover (θ)}_(W)=4°) for each. In certain embodiments, the beam patternincludes more than two nulling regions. FIG. 13 illustrates an exampleof coverage partition and initial weights for two nulling regions.

The above flowcharts illustrate example methods that can be implementedin accordance with the principles of the present disclosure and variouschanges could be made to the methods illustrated in the flowchartsherein. For example, while shown as a series of steps, various steps ineach figure could overlap, occur in parallel, occur in a differentorder, or occur multiple times. In another example, steps may be omittedor replaced by other steps.

Although the present disclosure has been described with exemplaryembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims. None of the description in this application should be read asimplying that any particular element, step, or function is an essentialelement that must be included in the claims scope. The scope of patentedsubject matter is defined by the claims.

What is claimed is:
 1. A base station (BS) in a wireless communicationsystem, the BS comprising: a transceiver; and a processor configured to:transmit a common beam to at least one user equipment (UE); andconfigure the common beam to have a null area in a direction of asatellite earth station, the null area defining a space within acoverage area of the common beam in which a signal from the common beamis suppressed.
 2. The BS of claim 1, wherein the processor is configuredto configure the common beam to have the null area by: partitioning acommon beam coverage area into a grid; identifying nulling units withinthe grid; assigning each of the nulling units an initial weight;determine a beam gain for each unit within the grid, including thenulling units; and determine a nulling width of the null area.
 3. The BSof claim 2, wherein the processor is further configured to determinewhether the nulling width satisfies a threshold for a given nullinglevel.
 4. The BS of claim 3, wherein, when the nulling width does notsatisfy the threshold, the processor is configured to change a weightassigned to each of the nulling units and determine the beam gain forthe each unit based on the changed weight.
 5. The BS of claim 2, whereinthe grid comprises equal-sized units according to a specifiedgranularity.
 6. The BS of claim 2, wherein the null area is disposedwithin at least one nulling unit.
 7. The BS of claim 1, wherein theprocessor is configured to configure the common beam to have at leastone or more null regions.
 8. A method comprising: transmitting, via atransceiver, a common beam to at least one user equipment (UE); andconfiguring the common beam to have a null area in a direction of asatellite earth station, the null area defining a space within acoverage area of the common beam in which a signal from the common beamis suppressed.
 9. The method of claim 8, wherein configuring the commonbeam to have the null area comprises: partitioning a common beamcoverage area into a grid; identifying nulling units within the grid;assigning each of the nulling units an initial weight; determine a beamgain for each unit within the grid, including the nulling units; anddetermine a nulling width of the null area.
 10. The method of claim 9,further comprising determining whether the nulling width satisfies athreshold for a given nulling level.
 11. The method of claim 10, furthercomprising, when the nulling width does not satisfy the threshold,changing a weight assigned to each of the nulling units and determiningthe beam gain for the each unit based on the changed weight.
 12. Themethod of claim 9, wherein the grid comprises equal-sized unitsaccording to a specified granularity.
 13. The method of claim 9, whereinthe null area is disposed within at least one nulling unit.
 14. Themethod of claim 8, wherein configuring the common beam comprisesconfiguring the common beam to have at least one or more null regions.15. A non-transitory computer readable medium comprising instructionsthat, when executed by at least one processor, cause the at least oneprocessor to: transmit a common beam to at least one user equipment(UE); and configure the common beam to have a null area in a directionof a satellite earth station, the null area defining a space within acoverage area of the common beam in which a signal from the common beamis suppressed.
 16. The non-transitory computer readable medium of claim15, wherein the instructions are further configured to cause the atleast one processor to configure the common beam to have the null areaby: partitioning a common beam coverage area into a grid; identifyingnulling units within the grid; assigning each of the nulling units aninitial weight; determine a beam gain for each unit within the grid,including the nulling units; and determine a nulling width of the nullarea.
 17. The non-transitory computer readable medium of claim 16,wherein the instructions are further configured to cause the at leastone processor to determine whether the nulling width satisfies athreshold for a given nulling level.
 18. The non-transitory computerreadable medium of claim 17, wherein, when the nulling width does notsatisfy the threshold, the instructions are further configured to causethe at least one processor to change a weight assigned to each of thenulling units and determine the beam gain for the each unit based on thechanged weight.
 19. The non-transitory computer readable medium of claim16, wherein the grid comprises equal-sized units according to aspecified granularity, and. wherein the null area is disposed within atleast one nulling unit.
 20. The non-transitory computer readable mediumof claim 15, wherein the instructions are further configured to causethe at least one processor to configure the common beam to have at leastone or more null regions.